Optimised assembly for detecting volatile compounds in a gaseous fluid, comprising a detector equipped with a suction tube and a vapour-sampling optimisation device

Abstract

An assembly for detecting volatile compounds in a gaseous fluid includes a detector for detecting vapours, equipped with a suction tube, and a vapour-sampling optimisation device. This vapour-sampling optimisation device has an end piece with a body having a through-passage extending along an axis in a suction direction and configured to accept the suction tube. The device also has a fluidic network with an inlet in fluidic communication with at least one outlet. When the gaseous fluid is injected into the end piece via the inlet of the fluidic network, the network forms a jet of gaseous fluid which is ejected from the end piece on either side of the suction direction. Each jet forms an angle of 10° to 90° in absolute value with the axis of the suction direction, so that the jet ejected from the end piece moves away from the suction axis.

1 . An assembly for detecting volatile compounds in a gaseous fluid, the assembly comprising:
 a detector for detecting vapours by suction, equipped with a suction tube; and   a vapour-sampling optimisation device, configured to be used in conjunction with the detector for detecting vapours by suction, the vapour-sampling optimisation device comprising:   an end piece having a body provided with:
 a through-passage, extending along an axis in a suction direction and configured to accept the suction tube; and 
 a fluidic network, which comprises an inlet and at least one outlet in fluidic communication with the inlet, the inlet and the at least one outlet between them defining a gaseous-fluid flow path; and 
   injection means, configured to inject the gaseous fluid into the fluidic network;   wherein the fluidic network is configured to, when the gaseous fluid is injected into the end piece via the inlet of the fluidic network, form at least one jet of gaseous fluid which is ejected from the end piece on either side of the suction direction, each jet forming an angle θ, in absolute value, of 10° to 90° with the axis of the suction direction, such that the jet of gaseous fluid ejected from the end piece moves away from the suction axis,   wherein the detector further comprises a chamber and a pump, configured to suck the gaseous fluid into the chamber through the suction tube, and   wherein when the assembly is operating, the end piece is positioned on the suction tube, and the gaseous fluid is simultaneously sucked into the chamber, by the pump, through the suction tube and injected into the inlet of the end piece by the injection means.   
     
     
         2 . The assembly of  claim 1 , wherein the injection means comprises a pump,
 wherein the pump used for sucking the gaseous fluid into the chamber and the pump used to inject the gaseous fluid into the end piece is one and the same pump.   
     
     
         3 . The assembly of  claim 2 , wherein the injection means further comprises a hose, in fluidic communication with the pump, to connect the pump to the inlet of the end piece. 
     
     
         4 . The assembly of  claim 1 , wherein each jet forms the same angle θ, in absolute value, with the axis of the suction direction. 
     
     
         5 . The assembly of  claim 1 , wherein the fluidic network comprises at least two outlets, the at least two outlets being positioned at the same height as one end of the through-passage, the fluidic network being configured so that the jets coming out of these two outlets belong to the same plane, the plane also comprising the suction direction. 
     
     
         6 . The assembly of  claim 1 , wherein the fluidic network comprises at least two outlets and a main channel that splits into at least two secondary channels, of which the at least two secondary channels are symmetrical in relation to a plane that includes the through-passage. 
     
     
         7 . The assembly of  claim 6 , wherein the secondary channels have a cross section that is constant. 
     
     
         8 . The assembly of  claim 6 , wherein the secondary channels have a cross section that reduces near the outlets. 
     
     
         9 . The assembly of  claim 1 , wherein the outlets have an elliptical shape. 
     
     
         10 . The assembly of  claim 1 , wherein the outlet is defined by a hollowed surface between two concentric shapes and centred on the through-passage, the two shapes being ellipses or polygons. 
     
     
         11 . A vapour-sampling optimisation method for detecting volatile compounds in a gaseous fluid using the assembly of  claim 1 , the method comprising:
 placing the suction tube in advance in the through-passage of the end piece; and   forming at least one jet on either side of the suction direction by sucking the gaseous fluid into the chamber through the suction tube and, simultaneously, injecting the gaseous fluid into the inlet of the fluidic network, which causes an ejection of the gaseous fluid via the at least one outlet in the form of at least one jet.   
     
     
         12 . The method of  claim 11 , wherein the suction and the injection are performed using one and the same pump.